Scattering rate collapse driven by a van Hove singularity in the Dirac semi-metal PdTe${}_2$

Abstract

We present optical measurements of the transition metal dichalcogenide PdTe${}_2$. The reflectivity displays an unusual temperature and energy dependence in the far-infrared, which we show can only be explained by a collapse of the scattering rate at low temperature, resulting from the vicinity of a van Hove singularity near the Fermi energy. An analysis of the optical conductivity suggests that below 150 K a reduction in the available phase space for scattering takes place, resulting in long-lived quasiparticle excitations. We suggest that this reduction in phase space provides experimental evidence for a van Hove singularity close to the Fermi level. Our data furthermore indicates a very weak electron-phonon coupling. Combined this suggests that the superconducting transition temperature is set by the density of states associated with the van Hove singularity.

4 pages, 3 figures

References in corpus (3)

• Type I superconductivity in the Dirac semimetal PdTe2
• Conventional Superconductivity in Type II Dirac Semimetal PdTe${}_2$
• Dominant $s$-wave superconducting gap in PdTe${}_2$ observed by tunneling spectroscopy on side-junctions

Cited by in corpus (3)

• Signatures of van Hove singularities in the anisotropic in-plane optical conductivity of the topological semimetal Nb${}_3$SiTe${}_6$
• Superconducting and structural properties of the type-I superconductor PdTe2 under high pressure
• Disorder induced transition from type-I to type-II superconductivity in the Dirac semimetal PdTe${}_2$